In the past, very few millimeter wave imaging cameras have been produced and millimeter wave detectors were typically machined as individual units and then hand assembled. The need for millimeter wave imaging arrays has increased, because of the need to detect concealed weapons and contraband hidden under clothing. Yngvesson, K. S.; Korzeniowski, T. L.; Kim, Y.-S.; Kollberg, E. L.; Johansson, J. F., “The tapered slot antenna-a new integrated element for millimeter-wave applications,” IEEE Trans. Microwave Theory Techniques,”, Vol. 37, No. 2, February 1989, pp. 365-374 describes a tapered slot antenna for millimeter wave applications. B. Kane, S. Weinreb, E. Fisher, and N. Byer, “High Sensitivity W-Band MMIC Radiometer Modules,” IEEE 1995 Microwave and Millimeter-Wave Monolithic Circuits Symposium Digest, 1995, pp. 59-62 describes a W-band module. Each of these references describes antennas or millimeter wave modules that are not modular. The designs in both these papers are not scalable to large arrays and are also not suitable for volume manufacturing.
U.S. Pat. No. 7,135,848 to D. F. Ammar describes a radiometer sensor cell for a scanning millimeter wave scanning imaging camera. The cell of Ammar is only suitable for building scalable imaging arrays having dimensions of 2×M, where M may be an arbitrary integer number. The cell of Ammar is quite large, so pixel resolution is low and the Ammar design is also not suitable for volume manufacturing.
What is needed is a modular scalable imaging array, which allows an arbitrarily large N×M array to be built. There is a need for a low-cost module design so that commercial quantities of imaging arrays can be produced in order to lower the cost of millimeter wave imaging cameras. The embodiments of the present disclosure answer these and other needs.